After putting her nearly 200-acre Millbrook estate on the market for $17.5 million, socialite Blaine Trump, the ex-sister-in-law of Donald Trump, has parked herself on Central Park South.

Trump and ex-husband Robert divorced in 2008. She continues to do philanthropic work in the city and has purchased a three-bedroom, two-bathroom duplex co-op at the Gainsborough building that was listed for $4.475 million. The duplex, at 222 Central Park South, features a 30-foot-long, double-height living area overlooking the park. The Gainsborough originated as an artist-studio building that dates back to 1907.

Now Trump needs to find a buyer for her Millbrook property. The estate includes an 8,000-plus-square-foot mansion, plus a carriage house and barns.

Greene is in fashion

The uptown set loves Proenza Schouler, the high-fashion designer label found in stores like Barneys, but the brand’s designers, Jack McCollough and Lazaro Hernandez, might be getting inspiration from the outer boroughs.

The duo recently headed to Brooklyn to check out a gorgeous $2.65 million townhouse at 433 Waverly Ave. in Fort Greene. The Southeast Asian-inspired carriage home is owned by Kathleen Perkins, who has gutted, decorated and flipped seven properties in New York.

The 22-foot-wide, three-story building on a landmarked block is currently split into rental units but could be transformed into a four- or five-bedroom residence with three private outdoor spaces and a garage.

The loft-like second floor includes a kitchen with limestone counters, double dishwashers, a Wolf range and exposed wooden beams and bricks along with a “sunny breakfast deck,” according to the listing. There’s also a full-floor master suite with vaulted ceilings, a terrace and a sky-lit, spa-like bathroom. Altogether, the home is 3,500 square feet and comes with two staircases.

Migrating north

Miami developer Don Peebles has moved to Manhattan. He’s renting a customized two-apartment combination at the Aldyn on Riverside Boulevard and sending his children to an Upper West Side private school.

Peebles is paying about $35,000 a month, sources say, for a roomy 4,750 square feet with a whopping seven bedrooms and 8 1/2 bathrooms. The residence has views facing south, east and west, including dramatic water vistas that the family enjoys. We hear that Peebles’ wife, Katrina, custom-designed the apartment’s interior, bringing in furniture, wallpaper and contemporary art.

‘Order’ out

“Law & Order” star Christopher Meloni and his wife, Sherman, still have their $9.95 million family condo at the Park Imperial on West 56th Street for sale. But that hasn’t stopped Meloni from buying a $4.383 million home in New Canaan, Conn. The mansion, on Oenoke Ridge, that he just purchased is a sprawling 8,063 square feet and sits on 4 acres. That’s a lot more space than the actor’s three-bedroom, 4 1/2-bathroom, 3,000-square-foot Park Imperial pad.

And while his Manhattan apartment is 60 floors up and boasts stunning Central Park views, Meloni’s new house comes with its own hot tub and pool. The five-bedroom, five-plus-bathroom residence also, according to the listing, has “extraordinary views to Manhattan” and a new “handsome six-stall or six-car” barn.

Broker Rita Kirby of William Pitt Sotheby’s did not return calls.

Ka-Cheng!

As owners of the BoConcept stores in the tristate area, Niki and Shaokao Cheng are no strangers to design.

And when their next-door neighbor at 260 Fifth Ave. told them he wanted to sell his apartment, the Chengs bought his co-op in a broker-free deal and are combining it with their existing home. Niki, an architect, is in charge of the redesign. BoConcept, a Denmark-based brand celebrating its 60th anniversary next month, will no doubt be featured.

The Chengs purchased their first 2,200-square-foot loft, an old sculptor’s studio, for $1.7 million in 2006 and spent about $250,000 renovating it. They paid an additional $1.38 million for the 1,600-square-foot addition last month. The combined home gives the Chengs five bedrooms, five bathrooms and a study. Renovations are expected to cost around $200,000.